Korotkoff sounds

Korotkoff sounds are the sounds that medical professionals listen for when they are taking blood pressure using a non-invasive procedure. These sounds are named after Dr. Nikolai Korotkoff, a Russian physician who discovered them in 1905. The sounds are heard through a stethoscope while a blood pressure cuff (sphygmomanometer) is used to restrict blood flow in an artery. Korotkoff sounds provide vital clues to the health of the cardiovascular system and are integral to diagnosing hypertension and other cardiovascular diseases.

Phases of Korotkoff Sounds

Korotkoff sounds are divided into five distinct phases as the pressure in the cuff is gradually released:

• Phase 1: The first detection of faint, clear tapping sounds that gradually increase in intensity. These sounds indicate the systolic blood pressure.
• Phase 2: A murmur or swishing sound follows phase 1 as the artery starts to open, allowing more blood flow.
• Phase 3: The sounds become crisper and louder, indicating further increase in blood flow.
• Phase 4: The sounds become muffled and softer. This phase is sometimes used to determine diastolic blood pressure in children and pregnant women.
• Phase 5: The final phase, where the sounds disappear completely. The pressure at which this occurs marks the diastolic blood pressure in adults.

Clinical Significance

Korotkoff sounds are essential for diagnosing and managing conditions related to blood pressure. Accurate measurement of systolic and diastolic blood pressure is crucial for identifying hypertension, assessing the risk of cardiovascular disease, and monitoring the effectiveness of treatments. Variations in the sounds or discrepancies between the phases can indicate specific vascular abnormalities or diseases.

Measurement Technique

To measure blood pressure and observe Korotkoff sounds, a healthcare provider will:

1. Place a blood pressure cuff snugly around the upper arm.
2. Inflate the cuff to a pressure higher than the expected systolic pressure.
3. Gradually release the pressure in the cuff while listening with a stethoscope placed over the brachial artery.
4. Note the pressures at which the Korotkoff sounds are first heard (systolic) and when they disappear (diastolic).

Limitations and Considerations

While the method of using Korotkoff sounds is widely practiced, it has limitations. The accuracy of the readings can be affected by the observer's hearing, background noise, and the patient's arm position. Additionally, some conditions, such as atrial fibrillation, can make it difficult to determine the phases accurately.

See Also

• Blood pressure
• Sphygmomanometer
• Hypertension
• Cardiovascular disease